Capaldi, who is the Twelfth Doctor, won’t regenerate as normal in the Series 10 finale which airs on BBC One this Saturday but instead will wait until the end of year special.

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Peter Capaldi will become the first Doctor Who to delay his regeneration until the Christmas special

The 59-year-old actor announced he was quitting the role in January and speculation has been rife as to who will take over as the next master of the Tardis.

Phoebe Waller-Bridge and Kris Marshall are the current front-runners but the BBC has insisted that no cast decision has been made yet.

It was always expected that Capaldi would say his final farewell in the festive episode but the latest trailer for the season finale showed him at the start of his regeneration process sparking speculation it could happen this weekend.

But showrunner Steven Moffatt – who is also walking away from the show this year and handing over the reins to Broadchurch creator Chris Chibnall – has confirmed the Twelfth Doctor will fight his fatal injury to live on.

Moffatt told Doctor Who Magazine: “The doctor is mortally wounded, staggering out of the Tardis into the snow and starting to regenerate.

“What you’re seeing is the beginning of the process.”

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Showrunner Steven Moffatt says the series 10 finale will show the start of the regeneration process

Viewers will witness the first signs of the transformation when the Doctor starts to glow but then the Time Lord finds a way to stop the process.

David Tennant’s Tenth Doctor was able to stop a regeneration in the 2008 episode, The Stolen Earth, after he wass shot by a Dalek’s ray.

SCARLETT AND DEC

SELLING PORKIES

But he manages to get inside the Tardis and siphon off his regeneration energy into his severed hand which was kept in a jar inside his space craft.

Capaldi will definitely regenerate in the Christmas Day story, in which he is rumoured to be joined on an adventure by The First Doctor, who will be played by David Bradley.

Bradley, 75, played William Hartnell – the first actor to portray the iconic character – in 2013 drama An Adventure in Space and Time, a dramatisation about the creation of Doctor Who.

Fans have already seen the Time Lord’s companion Bill Potts – played by Pearl Mackie – be converted into a Mondasian Cyberman, and the 30-year-old actress admitted it was very “emotional” shooting the plot because so much is about to happen.

Asked if it was “emotional filming the death of [her] character”, she said: “I mean, I’m quite an emotional person, so it was pretty emotional.

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Pearl Mackie said it was ‘very emotional’ filming the death of her character

“I mean even just reading any of it and at the read through it was quite emotional because there’s a lot of endings.

“I think that’s credit to Steven’s writing that you can get that kind of emotion from it when you read it that you’re supposed to get when you watch it.”